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+--- Thread: kaplan qbank - strongman (/showthread.php?tid=245667)
kaplan qbank - strongman - ArchivalUser - 11-23-2007
A 5-month-old male infant has a urine output of less than 0.1 mL/kg/hr shortly after undergoing
major surgery. On examination, he has generalized edema. His blood pressure is 94/48 mm
Hg, pulse is 140/min, and respirations are 20/min. His blood urea nitrogen is 38 mg/dL, and
serum creatinine is 1.4 mg/dL. Initial urinalysis shows a specific gravity of 1.018 and 2+
protein. Microscopic examination of the urine sample reveals 1 WBC per high-power field
(HPF), 18 RBCs per HPF, and 5 granular casts per HPF. His fractional excretion of sodium is
3.2 %. Which of the following is the most appropriate next step in diagnosis?
A. CT of the abdomen and pelvis
B. Cystourethrography
C. Intravenous pyelography
D. Renal biopsy
E. Renal ultrasonography
0 - ArchivalUser - 11-23-2007
EEEEE
BUN/Cr=38/1.4=27, he may have postrenal renal failure. So renal ultrasonic is indicated.
0 - ArchivalUser - 11-23-2007
this is atn ..as fc na is more than 2% and bun /cr is >10..granular cast too.
0 - ArchivalUser - 11-23-2007
?? this is a pre-renal mechanism.
0 - ArchivalUser - 11-23-2007
this is renal problem...fr sodium is more than 1%.....initial investigation at this point is USG..E
0 - ArchivalUser - 11-23-2007
Answer is D
This child has ATN secondary to hypotension after surgery as seen by tachycardia.
ATN- granular casts and Fe Na-3.2%. So biopsy confirms the diagnosis.
0 - ArchivalUser - 11-23-2007
Sorry, I am confused. It is a typical ATN: proteinuria, granular casts and fractional excretion of sodium is3.2 %.
So the acute renal failure results from ATN, which is caused by a ischemic or toxic injury to the kidney.
U/S should be the initial step to evaluate the structural and anatomic changes of the kidney.
E is the answer.
0 - ArchivalUser - 11-23-2007
Hi drdg,
I am sorry. The diagnosis is ATN and the investigation of choice is ultrasound. If the cause of ATN is unnown , even after the ultrasound biopsy should be considered as a last resort here.